Posted: Wed Apr 22, 2015 12:34 pm Post subject: USB not isolated?
After looking at the specs again just now, I noticed that the USB port is not isolated. What's the reason behind this? Won't this lead to problems when connecting a boat-powered / grounded laptop? Or is the powersupply of the multiplexer itself isolated perhaps?
Joined: Mar 26, 2006 Posts: 419 Location: Mannheim / Germany
Posted: Wed Apr 22, 2015 9:03 pm Post subject:
As with most NMEA devices, we have galvanic isolation on the NMEA-IN Ports.
We also have a galvanic isolated SeaTalk Port.
NMEA-OUT Ports and USB are not isolated.
I guess it might be good idea to implement this in the future.
If the computer is powered from a different power source ( Shore power ) , it might indeed result in ground loops between multiplexer and computer.
I actually think that even if the laptop is powered from the boat supply, there might be ground differences (my DC/DC converter that powers my laptop probably isn't really clean on its ground). At the very least you'd get a ground loop that could cause problems?
Adding it for a next version seems like a good plan, especially since it seems rather easy - just power the FT232 from USB and keep its ground separate, then add two high-speed optos on the RX and TX lines?
Now I'm doubting wether to get this multiplexer, or perhaps go for the miniplex after all. It's a lot of money to spend to run into problems later...
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